Birupes simoroxigorum, commonly known as the Borean neon-blue leg tarantula, is a strikingly beautiful Old World species endemic to the rainforests of Sarawak, Malaysia. First described in 2019, it is the only species in its genus and has become a high-demand "scientific celebrity" in the hobby due to its vibrant, electric-blue legs. 
 
Appearance & Identification
Coloration: Juveniles and females exhibit intense metallic blue legs that contrast with a creamy-toffee or peach-coloured carapace and a darker abdomen.
Sexual Dimorphism: Mature males lose the vivid blue coloration, becoming more slender and turning a uniform black or dark brown.
Size: This is a medium-sized tarantula, with adults reaching a diagonal leg span of 12 to 15 cm (5–6 inches). 
 
Natural Habitat & Lifestyle
Fossorial Nature: They are deep-burrowing "earth tigers" that spend the majority of their time in underground tunnels in humid rainforest floors.
Defensive Temperament: As an Old World species, they lack urticating hairs and are known to be fast, skittish, and potentially defensive. Their venom is considered more potent than that of New World species. 
 
Ethical Controversy
The description of this species was mired in controversy. Shortly after its publication in the Journal of the British Tarantula Society, allegations emerged that the original specimens used for scientific description had been illegally exported (poached) from Malaysia without the necessary permits from the Sarawak Forest Department. 
 
Captive Care (Intermediate/Advanced)
Due to its speed and environmental requirements, it is recommended for experienced keepers:
Environment: Requires high humidity (70–80%) and temperatures between 24°C and 28°C.
Enclosure: Needs deep substrate (at least 15 cm) to allow for its complex burrowing behavior.
Diet: Standard fare of crickets, roaches, or mealworms.